TimerTable.cc revision 10920:58fbfddff18d 
1/*
2 * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include "mem/ruby/structures/TimerTable.hh"
30#include "mem/ruby/system/System.hh"
31
32TimerTable::TimerTable()
33    : m_next_time(0)
34{
35    m_consumer_ptr  = NULL;
36    m_clockobj_ptr = NULL;
37
38    m_next_valid = false;
39    m_next_address = Address(0);
40}
41
42bool
43TimerTable::isReady() const
44{
45    if (m_map.empty())
46        return false;
47
48    if (!m_next_valid) {
49        updateNext();
50    }
51    assert(m_next_valid);
52    return (m_clockobj_ptr->curCycle() >= m_next_time);
53}
54
55const Address&
56TimerTable::readyAddress() const
57{
58    assert(isReady());
59
60    if (!m_next_valid) {
61        updateNext();
62    }
63    assert(m_next_valid);
64    return m_next_address;
65}
66
67void
68TimerTable::set(const Address& address, Cycles relative_latency)
69{
70    assert(address == line_address(address));
71    assert(relative_latency > 0);
72    assert(!m_map.count(address));
73
74    Cycles ready_time = m_clockobj_ptr->curCycle() + relative_latency;
75    m_map[address] = ready_time;
76    assert(m_consumer_ptr != NULL);
77    m_consumer_ptr->
78        scheduleEventAbsolute(m_clockobj_ptr->clockPeriod() * ready_time);
79    m_next_valid = false;
80
81    // Don't always recalculate the next ready address
82    if (ready_time <= m_next_time) {
83        m_next_valid = false;
84    }
85}
86
87void
88TimerTable::unset(const Address& address)
89{
90    assert(address == line_address(address));
91    assert(m_map.count(address));
92    m_map.erase(address);
93
94    // Don't always recalculate the next ready address
95    if (address == m_next_address) {
96        m_next_valid = false;
97    }
98}
99
100void
101TimerTable::print(std::ostream& out) const
102{
103}
104
105void
106TimerTable::updateNext() const
107{
108    if (m_map.empty()) {
109        assert(!m_next_valid);
110        return;
111    }
112
113    AddressMap::const_iterator i = m_map.begin();
114    AddressMap::const_iterator end = m_map.end();
115
116    m_next_address = i->first;
117    m_next_time = i->second;
118    ++i;
119
120    for (; i != end; ++i) {
121        if (i->second < m_next_time) {
122            m_next_address = i->first;
123            m_next_time = i->second;
124        }
125    }
126
127    m_next_valid = true;
128}
129